In order to inflate and deflate the tires forming part of the wheels on a vehicle, valves are located on the rims or hubs of the wheels to be used for selectively inflating and deflating the tires disposed around the wheel rims. Air can be directed through the valves either into or out of the tires to increase or decrease the air pressure in the tires, correspondingly altering the ride characteristics of the individual wheel, and the overall vehicle.
On most occasions the valves are only accessible from the exterior of the wheel, such that it is necessary to exit the vehicle to use the valve to inflate or deflate the tire. However, various central tire inflation systems have been developed that provide valves on the wheel rims that can be remotely activated from the cab or other driver compartment for the vehicle. These systems enable an individual to control the flow of air into and out of the vehicle tires using the valves to vary the ride characteristics of the tires as necessary. Examples of systems of this type are illustrated in each of Howald et al. U.S. Pat. No. 6,474,383, and Wang et al. U.S. Pat. No. 7,168,468, both of which are incorporated by reference herein. In each of theses patents, the rim of the wheel is formed with internal passages that enable air to be selectively passed from a compressed air supply through the passages to a valve. The valve is selectively operable from within the passenger compartment or cab of the vehicle to enable air to flow through the valve and into the tire through the passages formed in the rim. The passages are formed in either the outer rim (as in the '383 patent) or in the inner rim (as in the '468 patent) and form a flow path from an inlet for the compressed air through the rim and the associated valve to an opening on the exterior surface of the rim component that is located between the opposed sides of the wheel formed by the inner and outer rim sections. This outlet is also located between the beads of a tire mounted to the wheel, such that air exiting the outlet is retained within the tire to increase the air pressure, i.e., inflate the tire as desired.
Nevertheless, these prior art central tire inflation systems utilize passage designs that require the valves utilized therewith to have designs which require a number of additional components for the incorporation of the valves into tires for use with existing central tire inflation systems. These additional components greatly increase the cost and complexity of the valves, causing the valves to fail on a regular basis, necessitating that the valves be repaired and/or replaced on a consistent basis.
Additionally, the configuration of the passages in the rim in the prior art systems requires that the valve be positioned in an abutting relationship with the passages on the exterior surface of the rim component, i.e., surface-mounted on the rim. This positioning for the valve on the exterior of the rim in an exposed location where the valve can easily be damaged by debris or other objects striking the valve when the vehicle is in operation. In most instances, a wheel cover is required to protect the valve and other ancillary components for the central tire inflation system, such as hoses and fittings. The wheel cover is formed of steel or a composite material, and can trap rocks within the cover when in use, turning the cover into a rock tumbler that enables the rocks to damage the valve and other components of the CTIS system on the wheel that the cover is meant to protect.
As a result, it is desirable to develop a valve for use in a central tire inflation system that includes a minimum of parts and that can be incorporated into a number of different types of wheels. Also, it is desirable to develop a valve that can be positioned within a rim of a wheel incorporating a central tire inflation system that in a recessed or imbedded manner to effectively reduce the profile of the valve on the exterior of the wheel, thereby reducing the likelihood of the valve being struck and damaged during operation of the vehicle.